1. Field of the Invention
The present invention relates to a refrigerator, and more particularly, to an apparatus for generating heat of a refrigerator and a control method thereof capable of reducing the cost and simplifying a structure by using a lamp and a diode for lowering an applied voltage.
2. Description of the Background Art
In general, a refrigerator is divided into a freezing chamber for storing frozen food and a chilling chamber for storing chilled food, and a freezing cycle is provided therein to supply cool air to the freezing chamber and the chilling chamber.
Such a refrigerator is classified into a direct cooling type refrigerator employing a way of natural convection in which a cooling operation is performed by making air inside the refrigerator directly contact with an evaporator and an indirect cooling type refrigerator in which the cooling operation is performed by forming a duct, which cool air circulates through, inside the refrigerator and forcibly sending the cool air to the inside of the refrigerator by a blast fan.
The direct cooling type refrigerator is typically used for a small refrigerator having a small volume and the indirect cooling type refrigerator is typically used for a large refrigerator having a large volume.
FIG. 1 is a view showing a freezing cycle of the conventional direct cooling type refrigerator. As shown therein, a main body 15 of a refrigerator 11 is divided into an upper freezing chamber 4 and a lower chilling chamber 7, in which a freezing chamber evaporator 5 and a chilling chamber evaporator 6 are installed, respectively. In addition, a condenser 2 and a radiator 3 are installed at a rear surface of the exterior of the refrigerator 11, and a chamber having a compressor 1 or the like is disposed at a rear surface of a lower portion of the refrigerator.
Both the freezing chamber evaporator 5 installed in the freezing chamber 4 and the chilling chamber evaporator 6 installed in the chilling chamber 7 are direct cooling plate-shaped evaporators. The freezing chamber evaporator 5 has an area covering the surfaces, i. e. upper and lower surfaces and both side surfaces, other than a rear surface of the freezing chamber 4 and a door. Namely, the freezing chamber evaporator 5 is bent in a lattice type to cover the upper and lower surfaces and the both side surfaces of the freezing chamber. The chilling chamber evaporator 6 has a small area compared to the freezing chamber evaporator 5 and is attached to a rear surface of the chilling chamber 7.
Heat from a high temperature high pressure refrigerant discharged from the compressor 1 radiates passing through the condenser 2 and pressure of the refrigerant is reduced passing through a capillary tube 3, whereby the high temperature high pressure refrigerant becomes a low temperature low pressure refrigerant.
The low temperature low pressure refrigerant firstly absorbs heat passing through the evaporator of the freezing chamber 4, absorbs heat again passing through the chilling chamber evaporator 6, and is sucked into the compressor 1.
In the direct cooling type refrigerator, a surface temperature of an inner wall at which the evaporator 6 for chilling of the chilling chamber 7 is mounted is sensed, and according to the sensed temperature, an operation of the compressor 1 is controlled.
Namely, the direct cooling type refrigerator is designed to remain at a temperature of −18° C. and 3° C. for the freezing chamber 4 and the chilling chamber 7, respectively. According to the temperature sensed at the inner wall of the chilling chamber 7, driving of the compressor 1 is on/off, so that the temperature of the freezing chamber 4 and the chilling chamber 7 remains at a set temperature.
However,when outside air is below 10° C., an external load of the chilling chamber 7 is significantly reduced in comparison to that of the freezing chamber 4. Therefore, there is a problem that the compressor 1 is turned off before a temperature inside the freezing chamber 4 reaches −18° C. Namely, because there are not many external loads of the chilling chamber 7, a temperature inside the chilling chamber 7 easily reaches 3° C., which causes the compressor 1 not to operate before the temperature of the chilling chamber 7 reaches a target temperature.
Accordingly, in the conventional direct cooling refrigerator, a temperature which a temperature sensor senses is raised using a lamp 10 mounted in the chilling chamber 7 in case that weak cooling occurs before the temperature of the freezing chamber 4 reaches the target temperature because a temperature around the refrigerator is relatively low.
The lamp 10 is used for lighting when a door of the chilling chamber 7 is opened. It also functions as low temperature compensation for raising a temperature which the temperature sensor senses.
FIG. 2 is a schematic diagram showing a construction of a lamp heat generating apparatus of the conventional refrigerator. As shown therein, if the lamp 10 mounted at the chilling chamber 7 consumes the rectified power, the temperature inside the chilling chamber 7 is considerably raised to have a bad effect on controlling a temperature of the refrigerator 11. Accordingly, when the door of the refrigerator is closed, a switch 40 is turned off and a relay 30 is turned on such that a voltage is applied to both a lamp 10 and a capacitor 50. Therefore, the lamp 10 consumes the power lower than the rectification input to raise the temperature sensed by the temperature sensor of the refrigerator 11.
However, since the capacitor 50 which is used to lower the lamp 10 is expensive, economical efficiency is lowered. In addition, since the capacitor is comparatively bulky, a coupling structure is large and complicated.